Electromagnetic structure for reducing internal magnetic field intensity and stator loss of high-voltage phase modifier

Abstract

The invention discloses an electromagnetic structure for reducing the internal magnetic field intensity and stator loss of a high-voltage phase modifier, and the structure comprises a stator which is formed by arranging and stacking non-magnetic teeth; the non-magnetic teeth are formed by laminating a plurality of non-magnetic steel sheets with tooth groove structures; a tooth groove of the non-magnetic tooth is composed of a string of two-step gradually-increased round holes, the round holes are connected through narrow waists, and the eccentric distances of the two sides connected through the narrow waists are not equal. And the cable windings are placed in tooth grooves of the non-magnetic teeth and are isolated by the silicon rubber hoses. According to the electromagnetic structure for reducing the internal magnetic field intensity and the stator loss of the high-voltage phase modifier, the internal magnetic field intensity of the high-voltage phase modifier can be reduced, the stator loss can be reduced, the working voltage of the phase modifier is improved, the single-machine capacity and efficiency are improved, and it is guaranteed that output voltage and current meet regulations.

Description

Technical Field

[0001] The invention relates to the technical field of high-voltage phase regulators, and in particular to an electromagnetic structure for reducing the internal magnetic field strength and stator loss of high-voltage phase regulators. Background Art

[0002] High-voltage phase regulator is a rotating reactive power compensation device, which is mainly used to improve the stability of the power system and improve the power supply quality. It can quickly and automatically adjust the reactive power according to the needs of the system, which is equivalent to a generator set in a power plant. High-voltage phase regulator plays an important role in UHV DC transmission projects and is known as the "stability guard" of the power grid.

[0003] Compared with phase condensers using traditional conductors, high-voltage phase condensers have the characteristics of high current density and low resistance loss. However, the magnetic field strength inside the high-voltage phase condenser is too large, which causes the high-voltage phase condenser to fail to work normally. Summary of the invention

[0004] To solve the above problems, the present invention provides an electromagnetic structure for reducing the internal magnetic field strength and stator loss of a high-voltage phase regulator, thereby increasing the single-unit capacity of the phase regulator, improving the efficiency of the phase regulator, and ensuring that the output voltage and current meet the regulations.

[0005] To achieve the above object, the present invention provides an electromagnetic structure for reducing the internal magnetic field strength and stator loss of a high-voltage phase condenser, comprising:

[0006] The stator is composed of non-magnetic teeth arranged and stacked;

[0007] Non-magnetic teeth are made of a number of non-magnetic steel sheets with tooth groove structures laminated together;

[0008] The tooth groove of the non-magnetic tooth is composed of a series of two-stage gradually enlarged circular holes, which are connected by narrow waists, and the eccentric distances on both sides of the narrow waist connection are not equal;

[0009] The cable windings are placed in the tooth grooves of the non-magnetic teeth and isolated by silicone rubber hoses.

[0010] Preferably, the cable winding is made of cross-linked polyethylene cable, and the cable winding comprises a semiconductor layer, an insulating layer, an inner semiconductor layer, and a conductor from the outside to the inside, and the cable winding is arranged in a single-layer concentric structure.

[0011] Preferably, the cross-section of the silicone rubber hose is triangular, and the surface of the silicone rubber hose is serrated.

[0012] Preferably, the conductor is formed by twisting stranded wires.

[0013] Preferably, the thickness of the insulation layer increases step by step from the neutral point outwards, and the cable winding adopts step-by-step insulation.

[0014] Preferably, each branch winding of each phase of the cable winding is formed by connecting cables with different insulation thicknesses.

[0015] Preferably, the cable winding includes shielding damping, non-magnetic excitation winding support, stator back iron and rotating shaft in sequence, and the non-magnetic excitation winding is arranged inside the non-magnetic excitation winding support.

[0016] The electromagnetic structure of the present invention for reducing the internal magnetic field strength and stator loss of a high-voltage phase regulator has the following beneficial effects:

[0017] (1) The non-magnetic teeth are made of non-magnetic steel, which has a low magnetic permeability. The use of non-magnetic materials can reduce the magnetic field strength inside the high-voltage phase shifter, reduce the stator eddy current loss, and reduce the heat generation of the motor. At the same time, stainless steel materials have good corrosion resistance and high hardness, providing good structural support for the cable winding and having a long service life;

[0018] (2) A triangular silicone rubber hose is installed between the cable and the slot wall to reduce the vibration of the cable winding in the slot, provide appropriate support between the cable windings and between the cable and the slot wall, and leave an appropriate margin to cope with the pressure caused by the thermal expansion of the cable winding due to the increase in temperature when the phase regulator is working;

[0019] (3) The surface of the silicone rubber hose is designed to be serrated, leaving space for the plastic deformation of the hose and cable, and providing appropriate pressure between the cable and the tooth wall;

[0020] (4) By establishing a global discrete circuit network-finite element coupling model of a non-magnetic tooth high-voltage stator and analyzing the operating status of the high-voltage phase shifter, the rationality and feasibility of the electromagnetic design of the present invention are demonstrated.

[0021] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the overall structure diagram of the high voltage phase regulator;

[0023] Figure 2 This is the cable winding structure diagram;

[0024] Figure 3 It is a global discrete circuit network-finite element coupling model of a high-voltage stator with non-magnetic teeth for cable windings;

[0025] Figure 4 It is the magnetic field line distribution of high voltage phase regulator;

[0026] Figure 5 is the air gap magnetic flux waveform;

[0027] Figure 6 is the harmonic content of air gap magnetic density;

[0028] Figure 7 It is the radial magnetic density distribution cloud map;

[0029] Figure 8 It is the tangential magnetic density distribution cloud map;

[0030] Fig. 9 are the radial and tangential components of the yoke flux density;

[0031] Fig.10 It is the waveform of fundamental induced electromotive force of each layer of cable winding;

[0032] Fig.11 is the line voltage waveform;

[0033] Fig.12 is the stator current of the phase regulator during delayed phase operation;

[0034] Fig.13 The phase relationship between the current and voltage of phase A of the condenser during delayed phase operation;

[0035] Fig.14 This is the distribution cloud diagram of magnetic field lines during delayed phase operation;

[0036] Fig.15 is the steady-state direct-axis magnetic field line;

[0037] Fig.16 is the steady-state direct-axis magnetic flux vector diagram;

[0038] Fig.17 is the steady-state direct-axis magnetic field intensity vector diagram;

[0039] Fig.18 is the steady-state cross-axis magnetic field line;

[0040] Fig.19 is the steady-state cross-axis magnetic flux vector diagram;

[0041] Fig. 20 is the steady-state cross-axis magnetic field intensity vector diagram;

[0042] Fig.21 is the short-circuit current of phase A;

[0043] Fig. 22 is the short-circuit current of phase B;

[0044] Fig.23 is the short-circuit current of phase C;

[0045] Fig.24 is the excitation current waveform;

[0046] Fig.25 is the envelope of the transient waveform of the short-circuit current of phase A;

[0047] Fig.26are the periodic component and non-periodic component of the A phase short-circuit current;

[0048] Fig. 27 is the fitting curve of the non-periodic component of the short-circuit current of phase A;

[0049] Fig.28 is the fitting curve of the non-periodic component of the short-circuit current of phase B;

[0050] Fig.29 is the fitting curve of the non-periodic component of the C phase short-circuit current;

[0051] Fig.30 is the double exponential fitting of the periodic component of the short-circuit current.

[0052] Reference numerals

[0053] 1. Non-magnetic teeth; 2. Cable winding; 3. Silicon rubber hose; 4. Shielding damping; 5. Non-magnetic excitation winding support; 6. Excitation winding; 7. Stator back iron; 8. Rotating shaft; 9. Outer semiconductor layer; 10. Insulation layer; 11. Inner semiconductor layer; 12. Conductor. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical scheme and advantages disclosed in the embodiments of the present invention clearer, the embodiments of the present invention are further described in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not intended to limit the embodiments of the present invention. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions.

[0055] It should be noted that the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or server that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products or devices.

[0056] Like reference numerals and letters denote similar items in the following drawings, and thus, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0057] Embodiment 1

[0058] An electromagnetic design structure of a high voltage phase regulator stator, such as Figure 1As shown, it includes non-magnetic teeth 1, cable windings 2, shielding damping 4, non-magnetic excitation winding supports 5, stator back iron 7 and rotating shaft 8 which are sequentially sleeved from the outside to the inside. The stator is stacked by non-magnetic teeth 1, and the excitation winding 6 is arranged inside the non-magnetic excitation winding supports 5.

[0059] The non-magnetic tooth 1 is made of non-magnetic steel 316L thin sheets with tooth groove structure. The groove type of the non-magnetic tooth 1 is composed of a series of two-stage gradually increasing circular holes, and the circular holes are connected by a narrow waist, and the eccentric distances on both sides of the narrow waist connection are not equal.

[0060] The magnetic permeability of non-magnetic steel is low. The use of non-magnetic materials can reduce the magnetic field strength inside the high-voltage phase regulator, reduce stator eddy current losses, and reduce the heat generation of the motor. At the same time, stainless steel materials have good corrosion resistance and high hardness, providing good structural support for the cable winding 2 and having a long service life.

[0061] The cable winding 2 is placed in the non-magnetic tooth slot, and a triangular silicone rubber hose 3 is provided between the cable winding 2 and the slot wall for isolation to reduce the vibration of the cable winding 2 in the slot, provide appropriate supporting force between the cable windings 2 and between the cable and the slot wall, and leave appropriate margin to cope with the pressure caused by thermal expansion of the cable winding 2 due to the increase in temperature when the phase regulator is working.

[0062] The surface of the silicone rubber hose 3 is serrated, which leaves space for plastic deformation of the silicone rubber hose 3 and the cable and provides appropriate pressure between the cable and the tooth wall.

[0063] The structure of cable winding 2 is as follows Figure 2 As shown, it includes an outer semiconducting layer 9, an insulating layer 10, an inner semiconducting layer 11, and a conductor 12. The cable winding 2 is wound with a cross-linked polyethylene cable. In order to minimize the influence of the winding on the insulation performance of the cable, the cable winding 2 is arranged in a single-layer concentric structure. The conductor 12 is made of stranded wires.

[0064] The thickness of the insulating layer 10 increases step by step from the neutral point outwards, the cable winding 2 adopts step-by-step insulation, and each branch winding of each phase is formed by connecting cables with different insulation thicknesses.

[0065] Embodiment 2

[0066] An electromagnetic analysis method for a high-voltage phase condenser stator includes two parts: establishing a global discrete circuit network-finite element coupling model of a high-voltage phase condenser magnetic gear high-voltage stator and analyzing the operation status of the high-voltage phase condenser.

[0067] The operating status analysis of high-voltage phase regulator includes: no-load state simulation, delayed phase operating state analysis, direct-axis and quadrature-axis magnetic field analysis, and reactance parameter calculation; thereby ensuring that the output voltage and current are within the specified range while reducing the internal magnetic field strength of the high-voltage phase regulator to increase the capacity and efficiency of the phase regulator.

[0068] Establishing the global discrete circuit network-finite element coupling model of the high-voltage phase-converter magnetic gear high-voltage stator includes:

[0069] (1) Taking a single winding cable as the basic unit, a finite element coupling model of the cable winding's global discretized circuit network and electromagnetic field is constructed to quantitatively characterize the magnitude and waveform variation law of the electromotive force of each coil turn and the key influencing factors, explore the balance relationship between winding utilization, tooth loop length and high voltage output guarantee, and ensure that the voltage output size and waveform distortion rate of the high-voltage phase-shifting machine meet the requirements.

[0070] In order to simplify the analysis, the magnetic field generated by the displacement current is ignored, and the electromagnetic field inside the phase regulator is assumed to be a quasi-steady field, and the electromagnetic field inside the phase regulator is considered to be a two-dimensional distribution. At this time, the two-dimensional transient electromagnetic field differential equation of the phase regulator is:

[0071]

[0072] Among them, A Z is the axial component of the magnetic vector potential; J Z is the axial component of the current density, v is the magnetic resistivity of the material; σ is the electrical conductivity of the material, Γ l and Γ2 are the boundaries between the outer circle of the stator back iron and the inner circle of the rotor back iron.

[0073] The second-order triangular element is used to discretize the solution area. The total number of nodes of the finite element model after segmentation is set to N. node , A Z and J Z After discretization, the discretization equation of the transient electromagnetic field can be obtained as follows:

[0074] -Q·pA z -K.A z +C·I b =0;

[0075] Among them, A Z N node is the column vector to be determined; Q and K are coefficient matrices related to node coordinates; p is the differential operator; I b is the conduction current matrix, including the current in the stator and the excitation coil; C is the correlation matrix between the conduction current and the nodes.

[0076] The cable winding model is discretized in the entire domain, and the voltage equation is constructed with each branch, each coil, and each layer of a single cable rod as the basic unit.

[0077] Ignoring the mutual leakage inductance at the ends of each layer of cable coils, the voltage equation of the k-th layer coil of the j-th branch is:

[0078] U i,j,k = l ef p|A zi,j,k-A zi,j+y,k |+L Ej,k pI b +I b (R E +R L );

[0079] Among them, U i,i,k is the voltage of the k-th coil of the j-th branch; A zi.i,k and A zi,i,k+v.k is the vector magnetic potential at the center line of the two cable bars of the k-th coil, calculated by the finite element model; y is the winding pitch; L Ei,k is the end leakage inductance of the j-th k-th layer cable coil; R E and R are the resistances of the cable coil end and the straight section, which can be calculated based on the geometric parameters of the cable coil; l ωf It is the effective axial length of the phase regulator core.

[0080] The voltage equation of the i-th branch is:

[0081] U i = l ef pA zi +M Ei pI b +N c N s I b (R E +R L );

[0082]

[0083] Among them, M Ei is the leakage inductance at the end of the i-th branch cable winding, N c is the number of conductors per slot, N s is the number of branch coils.

[0084] Assuming that the stator has N branches, the stator phase voltage equation is:

[0085] U=l ef pA z +M E p·I+RI;

[0086] Among them, U=[U1 U2…U N ] T ,U=[U1 U2…U N ] T ;

[0087]

[0088] The excitation circuit voltage equation is the same as that of the synchronous generator.

[0089] The relationship between the coil current matrix and the branch current matrix is ​​I b =G·I;

[0090] Among them, G is the correlation matrix between coil current and branch current, which can be determined by the winding connection topology.

[0091] Let M = G·C to adjust the camera's global axial magnetic position A Z The discrete network-finite element coupling model with the conductor current I as an unknown quantity is as follows: Figure 3 As shown:

[0092]

[0093] (2) Based on the global discrete circuit network-finite element coupling model of the non-magnetic tooth high-voltage stator, the no-load state analysis is carried out.

[0094] like Figure 4 The figure shows the distribution of magnetic lines of force of the high-voltage phase regulator. It can be seen that due to the non-magnetic tooth structure of the stator, the magnetic resistance of the main magnetic circuit is greatly increased, resulting in part of the magnetic field not being closed by the stator yoke, and the magnetic field linked by the cable winding from the slot to the bottom of the slot gradually decreases, and the cable winding turn potential gradually decays from the slot to the bottom of the slot, resulting in a decrease in the utilization rate of the cable winding.

[0095] like Figure 5 As shown, it is the air gap magnetic flux waveform; Figure 6 As shown, part A is the air gap magnetic flux harmonic content curve, and part B is the air gap magnetic flux fundamental amplitude statistics. Due to the high magnetic load of the high-voltage phase condenser, the air gap magnetic flux contains odd harmonics mainly composed of the third harmonic, and because the stator adopts a non-magnetic tooth structure, the air gap magnetic flux is less affected by the tooth harmonics. After analysis, the air gap magnetic flux fundamental amplitude is 1.37T, the third harmonic amplitude is 0.052T, the fifth harmonic amplitude is 0.041T, and the seventh harmonic amplitude is 0.028T, accounting for less than 5% of the fundamental wave.

[0096] like Figure 7 , Figure 8As shown in the figure, the distribution and variation cloud diagram of the radial and tangential flux density of the non-magnetic tooth part along the radial direction of the tooth in one cycle. It can be seen that the distribution of the flux density of the non-magnetic tooth part is significantly different from that of the conventional motor. Because the magnetic resistance of the non-magnetic tooth part is large, the tooth part flux density has a large tangential component, and both the radial and tangential flux density have obvious attenuation along the radial direction of the tooth part. Near the tooth top, the radial flux density amplitude is 1.34T, and the tangential flux density amplitude is 0.74T; near the tooth root, the radial flux density amplitude is 0.75T; the tangential flux density amplitude is 0.04T. The radial flux density decays by 44.0% from the tooth top to the tooth root, and the tangential flux density decays by 94.6% from the tooth top to the tooth root. The radial component of the flux density of the non-magnetic tooth part is mainly the fundamental wave, while the tangential component of the flux density of the non-magnetic tooth part contains a certain odd harmonic component, of which the amplitude of the third harmonic is 0.043T, accounting for 5.8% of the fundamental wave.

[0097] like Fig. 9 As shown in the figure, the radial and tangential components of the yoke magnetic flux density are shown. It can be seen that the yoke magnetic flux density is mainly tangential, with an amplitude of 1.15T, and the yoke magnetic flux density is within a reasonable range.

[0098] According to the high-voltage stator global discrete circuit network-finite element coupling model calculation, the induced electromotive force of the ten-layer cable rod in the same slot can be obtained, as follows: Fig.10 As shown. The fundamental amplitude of the electromotive force of each layer of wire rods is: 235.7V for the first layer, 225.6V for the second layer, 217.6V for the third layer, 210.8V for the fourth layer, 205.2V for the fifth layer, 200.2V for the sixth layer, 195.9V for the seventh layer, 192.6V for the eighth layer, 190.4V for the ninth layer, and 189.0V for the tenth layer. The amplitude of the induced potential of each layer of wire rods is not much different. The electromotive force of the tenth layer of wire rods is 80.2% of that of the first layer, and the closer to the bottom of the slot, the smaller the difference in the electromotive force of the wire rods. The electromagnetic scheme has been verified to be feasible.

[0099] (3) When the stator of a high-voltage phase-shifting condenser adopts special structures such as non-magnetic teeth and cable windings, it is necessary to comprehensively consider factors such as output voltage, winding utilization, number of conductors per slot, and main dimensions of the phase-shifting condenser, construct a global discrete circuit network-finite element coupling model of the cable winding, and conduct an accurate quantitative analysis of the electromagnetic scheme of the high-voltage superconducting phase-shifting condenser with non-magnetic teeth of the cable winding, in order to seek a coordinated matching relationship between high voltage output and material utilization.

[0100] like Fig.11 The figure shows the line voltage waveform of the high voltage phase regulator. It can be seen that the line voltage waveform basically changes according to the sine law, and its fundamental amplitude is 49.25kV, which meets the output voltage requirements. The 5th harmonic voltage amplitude is 91.5V, accounting for only 0.18% of the fundamental wave. The line voltage waveform sine distortion rate is only 0.17%, which meets the engineering requirements.

[0101] (4) Connect the high-voltage phase regulator to the grid and keep the phase regulator's no-load potential in phase with the grid voltage. Increase the rotor excitation current to make the phase regulator run in a delayed phase state. Adjust the excitation current to make the phase regulator output rated inductive reactive power. At this time, the phase regulator's stator current is the rated current. Fig.12 As shown in the figure, the phase relationship between the current and voltage of phase A of the condenser during delayed phase operation is as follows: Fig.13 As shown in the figure, the magnetic field line distribution cloud diagram during delayed phase operation is as follows Fig.14 As shown in the figure, the voltage and current waveforms, and the magnetic field line distribution are all within the requirements, which has verified the feasibility of the electromagnetic scheme.

[0102] (5) Open the excitation winding and analyze the steady-state direct-axis and quadrature-axis magnetic fields of the condenser. The steady-state direct-axis magnetic field lines, magnetic flux density vector diagram, and magnetic field intensity vector diagram of the condenser are shown in Figure 1. Fig.15 , 16 , 17; steady-state cross-axis magnetic field lines, magnetic density vector diagram, and magnetic field intensity vector diagram are shown respectively as Fig.18 , 19 , as shown in Figure 20. When the high-voltage phase shifter is in steady state, the distribution of direct-axis magnetic force lines, magnetic flux density, and magnetic field strength, as well as the distribution of quadrature-axis magnetic force lines, magnetic flux density, and magnetic field strength are all in accordance with normal conditions and meet engineering requirements.

[0103] (6) In order to achieve high-voltage output, the number of cable winding turns needs to be increased. The increase in the number of winding turns causes the non-magnetic tooth loop to grow, which leads to an increase in leakage flux. The increase in leakage flux will reduce the cable winding utilization rate, so the number of cable winding turns needs to be increased. In order to avoid possible vicious cycle problems, a single winding cable is used as the basic unit to construct a global discretized circuit network and electromagnetic field finite element coupling model of the cable winding. The established high-voltage phase-shifting field circuit coupling model is used to quantitatively characterize the magnitude and waveform change law of the electromotive force of each coil turn and the key influencing factors. A three-phase sudden short-circuit simulation analysis is carried out under the no-load state of the phase-shifting machine. The stator current and excitation current waveforms under three-phase short-circuit are obtained to explore the balance between winding utilization, tooth loop length and high-voltage output guarantee, and to ensure that the voltage output size and waveform distortion rate of the high-voltage phase-shifting machine meet the requirements. The short-circuit currents of the three phases A, B and C are as follows: Fig.21 , Fig. 22 , Fig.23 As shown, the excitation current waveform is as follows Fig.24 shown.

[0104] The reactance parameters and corresponding time constants of the phase regulator have an important influence on the dynamic performance of the phase regulator.

[0105] The model is calculated using the time domain method, the electromagnetic field equation is combined with the external circuit equation, and the time and space are discretized and solved jointly. The stator and rotor current curves obtained by simulation are analyzed, and the transient and supertransient reactance parameters and the corresponding time constants are obtained using curve fitting methods.

[0106] When a three-phase symmetrical short circuit occurs suddenly during no-load operation of the generator, the A-phase current expression is as follows:

[0107]

[0108] Where E0 is the effective value of the no-load phase potential, x d is the direct-axis synchronous reactance, x′ d , x″ d is the direct-axis transient and supertransient reactance, T′ d , T″ d is the direct axis transient and super transient time constant, α0 is the initial phase of the short-circuit current.

[0109] For the above A-phase short-circuit current curve, the fundamental component and the non-periodic component are decomposed. The specific processing method is as follows:

[0110] ① First, the upper and lower envelopes of the current waveform of each phase are obtained by connecting the peak values ​​of each cycle of the current waveform, and then the amplitude of the fundamental component of the short-circuit current is obtained by taking half of the algebraic difference of the ordinates of the upper and lower envelopes at any moment;

[0111] ② Take half of the algebraic sum of the ordinates of the upper and lower envelopes at any instant to obtain the amplitude of the non-periodic component of the short-circuit current. The envelope of the transient waveform of the short-circuit current of phase A is as follows: Fig.25 As shown, the periodic component and non-periodic component of the short-circuit current of phase A are as follows Fig.26 shown.

[0112] During the no-load three-phase sudden short circuit of the high-voltage phase regulator, the amplitude of the periodic component of the A-phase short-circuit current is as follows:

[0113]

[0114] During the no-load three-phase sudden short circuit of the phase regulator, the amplitude of the non-periodic component of the A phase short-circuit current can be expressed as:

[0115]

[0116] The amplitude curve of the periodic component is fitted with a double exponential and the non-periodic component is fitted with a single exponential to obtain the direct-axis steady-state, transient and super-transient reactance of the phase regulator and the corresponding transient and super-transient time constants. The fitting curves of the non-periodic components of the short-circuit current of the three phases A, B, and C are shown in Figure 2. Fig. 27 , Fig.28 , Fig.29 shown.

[0117] The direct-axis reactance parameters and related time constants of the high-voltage phase regulator are calculated by exponential fitting of the three-phase short-circuit current. The reactive output characteristics of the phase regulator mainly depend on its direct-axis parameters, among which the key to the sub-transient reactive output is x d ′ and x″ d The smaller the sum of the two, the better the transient reactive response characteristics, the smaller the direct axis open circuit time constant, and the faster the transient reactive response of the phase regulator. The double exponential fitting curve of the short-circuit current periodic component is as follows: Fig.30 shown.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. An electromagnetic structure for reducing the internal magnetic field strength and stator loss of a high-voltage phase condenser, characterized in that: include: The stator is composed of non-magnetic teeth arranged and stacked; Non-magnetic teeth are made of a number of non-magnetic steel sheets with tooth groove structures laminated together; The tooth groove of the non-magnetic tooth is composed of a series of two-stage gradually enlarged circular holes, which are connected by narrow waists, and the eccentric distances on both sides of the narrow waist connection are not equal; The cable windings are placed in the tooth grooves of the non-magnetic teeth and isolated by silicone rubber hoses.

2. The electromagnetic structure for reducing the magnetic field strength and stator loss inside a high-voltage phase condenser according to claim 1, characterized in that: The cable winding is made of cross-linked polyethylene cable. From the outside to the inside, the cable winding is a semiconductor layer, an insulating layer, an inner semiconductor layer, and a conductor. The cable winding is arranged in a single-layer concentric structure.

3. The electromagnetic structure for reducing the internal magnetic field strength and stator loss of a high-voltage phase condenser according to claim 1, characterized in that: The cross section of the silicone rubber hose is triangular, and the surface of the silicone rubber hose is serrated.

4. The electromagnetic structure for reducing the internal magnetic field strength and stator loss of a high-voltage phase condenser according to claim 2, characterized in that: The conductor is made of stranded wires twisted together.

5. The electromagnetic structure for reducing the magnetic field strength and stator loss inside a high-voltage phase condenser according to claim 2, characterized in that: The thickness of the insulation layer increases gradually from the neutral point to the outside, and the cable winding adopts step-by-step insulation.

6. The electromagnetic structure for reducing the magnetic field strength and stator loss inside a high-voltage phase condenser according to claim 5, characterized in that: Each branch winding of each phase of the cable winding is composed of cables with different insulation thicknesses.

7. The electromagnetic structure for reducing the magnetic field strength and stator loss inside a high voltage phase condenser according to claim 1, characterized in that: The cable winding is provided with shielding damping, non-magnetic excitation winding support, stator back iron and rotating shaft in sequence, and the non-magnetic excitation winding is arranged inside the non-magnetic excitation winding support.

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